1. Field of the Invention
This invention relates to a keyboard, video, mouse (KVM) switch, and in particular, it relates to a KVM switch with picture-in-picture (PIP) functions.
2. Description of the Related Art
In a keyboard, video, mouse (KVM) switch system, a plurality of computers is connected to one or more user consoles via a KVM switch. Each user console includes a video display device (monitor), user input devices such as a keyboard and a mouse, and audio speakers (optional). Each computer is connected to a computer port and each user console is connected to a console port of the KVM switch. The KVM switch has a routing matrix to selectively connect each console port to a computer port. Thus, each user console can selectively access and control one of the computers as if the user console is directly plugged into that computer. The KVM switch typically implements an on-screen display (OSD) menu system to allow the user to interact with the KVM switch and control its functions, e.g., logging on to the switch, selecting which computer to access, etc.
In some KVM switch systems, a picture-in-picture (PIP) function is implemented in the KVM switch to allow the user to see video signals (desktop images) from multiple computers simultaneously. For example, U.S. Pat. No. 7,240,111 describes a KVM switch called a “management device” where desktop images, called “host windows”, from multiple computers are displayed simultaneously on the monitor of the user console, see FIGS. 3 and 4 of that reference. This system allows the user to navigate among the computers by moving the mouse over the host window of the desired computer. The management device uses hardware to implement the PIP functions. In particular, the video signal displayed on the console monitor is generated by the management device using video signals from the multiple computers as input.